Flat panel displays are increasingly used in various commercial products and fields in recent years and larger, higher-image-quality, and low-power-consumption flat panel displays are in demand.
Under such trends, organic EL devices equipped with organic EL elements that use electroluminescence of organic materials are attracting much attention as display devices for flat panel displays that excel in terms of low-voltage drive, high-speed response, self luminous property, etc., despite being in an all-solid state.
An organic EL device includes, for example, a thin film transistor (TFT) and an organic EL element connected to the TFT on a substrate, such as a glass substrate. The organic EL element has a structure in which a first electrode, an organic electroluminescence layer (hereinafter may also be referred to as an organic EL layer), and a second electrode are stacked on top of each other in that order. The first electrode is coupled to the TFT. The organic EL layer has a structure in which layers such as a hole injection layer, a hole transport layer, an electron blocking layer, an emission layer, a hole blocking layer, an electron transport layer, and an electron injection layer are stacked on top of each other.
An organic EL device for full color displays usually includes subpixels constituted by organic EL elements of three colors, red (R), green (G), and blue (B), and these subpixels are arranged in a matrix so that the subpixels of three colors constitute one pixel. An image is displayed when these organic EL elements are selectively caused to emit light at a desired luminance.
In producing such an organic EL device, a pattern of emission layers are formed by using a light-emitting material so as to correspond to the organic EL elements (subpixels) of respective colors.
Examples of the method for forming a pattern of emission layers proposed include a method with which vapor deposition is performed by bringing a substrate and a vapor deposition mask about the same size as the substrate into contact with each other (hereinafter this method may be referred to as a contact deposition method) and a method with which vapor deposition is carried out while moving a substrate relative to a vapor deposition mask smaller than the substrate in size (hereinafter this method may be referred to as a scan deposition method). The following techniques related to the scan deposition method have been disclosed, for example.
Disclosed is a thin-film vapor deposition apparatus for forming a thin film on a substrate, the apparatus including a vapor deposition source; a first nozzle arranged on one side of the vapor deposition source and having a plurality of first slits formed along a first direction; a second nozzle arranged to oppose the vapor deposition source and having a plurality of second slits formed along the first direction; a blocking wall assembly that includes a plurality of blocking walls arranged along the first direction so as to partition a space between the first nozzle and the second nozzle; and at least one selected from a spacing controlling member that controls spacing between the second nozzle and the substrate and an alignment controlling member that controls alignment between the second nozzle and the substrate (for example, see PTL 1).
Also disclosed is a method for producing an organic EL element that includes a coating film of a particular pattern on a substrate, the method including a vapor deposition step of forming the coating film by causing vapor deposition particles to adhere to the substrate. The vapor deposition step is a step in which a vapor deposition unit, which includes a vapor deposition source including a vapor deposition source opening through which vapor deposition particles are released and a vapor deposition mask disposed between the vapor deposition source opening and the substrate, is used. In this step, while holding the substrate distant from the vapor deposition mask by a particular distance, one of the substrate and the vapor deposition unit is relatively moved with respect to the other so that the vapor deposition particles that have passed through the mask openings formed in the vapor deposition mask are caused to adhere to the substrate. When the relative movement direction between the substrate and the vapor deposition unit is assumed to be a first direction and a direction orthogonal to the first direction is assumed to be a second direction, the vapor deposition unit includes a plurality of limit plates between the vapor deposition source opening and the vapor deposition mask and at different positions in the second direction. Each of the plurality of limit plates limits the incident angle of the vapor deposition particles entering each of the plurality of mask openings when viewed along the first direction (For example, see PTL 2).